Conventional Therapies for Degenerative Disc and Other Cartilage Disease
Considering knee degeneration or osteoarthritis (“OA”) as an example, pain in knee OA, defined as loss of articular cartilage in the knee, is thought to be caused by increased pressure on the subchondral bone. Thus, there are changes in subchondral bone marrow that can be seen at the earliest stages of the onset of OA (Lorieg et al, Rheum 7: 43-49, 2011).
Current technologies for treating knee OA include non-steroidal anti-inflammatory drugs (Nsaids) including the newer Cox-2 inhibitors. Although these medications decrease inflammation and pain, their prolonged use (i) is thought to have an adverse impact on cartilage and (ii) comes with complications of increased risk of hypertension, coronary artery disease, renal failure (especially in diabetics) and peptic ulcer disease.
Hyaluronic acid (HA) has been shown to have some positive impact on cartilage. However, it has limited success rates in treating knee OA. Thus, while some studies show good success rates, others show rather poor ones. Furthermore, success rates decrease substantially in those patients with moderate to severe knee OA.
Microfracture has been used for a very small subset of knee OA patients with small cartilage defects. This technique has seen limited success rates. The technique functions by creating fibrocartilage. However, if done excessively, microfracture can sometimes even accelerate the rate of cartilage loss.
Finally, total and partial knee replacements have been used. These procedures have significant complication rates of blood clots and infections, are expensive, require hospital stays, have the associated liability of inserting metal in the body, and come with markedly increased healthcare costs.
Conventionally, when delivering a therapeutic agent to a hard to reach anatomical area, such as, for example, the bone-chondral interphase (BCI), a drill is used to create a pathway. Generally, a device with a central cannula is used, which is initially provided with a miniature drill shaft and drill bit within it.
The practitioner drills into the bone, and then removes the drill shaft and bit from the central cannula. Then a stylet is inserted, thus isolating the bone tissue from the outside environment. Finally, the stylet is removed and one of various appropriate therapies (e.g., drug, biologic or therapeutic) can be delivered via a syringe or other delivery device.
This conventional procedure thus twice exposes the internal tissue to ambient air. Once when the drill shaft and bit are removed and replaced with a stylet, and again when the stylet is removed to introduce a therapeutic agent. Each time internal tissues are exposed in this way the risk of infection increases. Furthermore, this is technically more challenging and time consuming with increased risk of complications.
What is thus needed in the art are exemplary devices and methods to reach internal anatomical areas which at the same time decreases the exposure of internal tissues to ambient air and reduces trauma. What are further needed in the art are therapeutics and methods of treatment to address loss of cartilage, and devices that enable simpler delivery of such therapeutics in less time, with reduced trauma, so as to reduce the risk of complications.